Typically, prior art aerosol collection instruments use filters in which air is drawn therethrough by means of a pump. A pump is used because the pressure drop across a filter rises sharply with particle loading. However, pumps are suitable for moving air across a large pressure drop, though in relatively small amounts.
Also pumps are relatively heavy and noisy and require a relatively large battery pack to power same if one is to have a portable unit.
Because of the weight of the above assembly, it is divided into two units to assist the wear-ability thereof. That is, the collection surface of the sampler is a filter inside a housing clipped, e.g., to the collar of the wearer, while the pump and battery pack are worn on the belt of the wearer and the two units are connected by, e.g., a plastic air hose, as illustrated in FIG. 6 hereof.
Typically the pump box and battery pack weigh a pound or more. Also the pump is relatively loud and rather noticeable if worn indoors, to the discomfort of the wearer.
That is, in prior art air samples, the inlet system is in the breathing zone of the wearer and the pumping system is worn at his waist, which can be for a period of several hours, to the further discomfort of the wearer. For related prior art samplers, see U.S. Pat. No. 5,693,895 to Baxter and U.S. Pat. No. 6,170,342 to Walter.
There has now been discovered a compact, light weight air sampler that is a one part rather than a two part unit, that is eminently wearable, less conspicuous and comfortable to wear for extended periods as further described below.